Cryptochrome, Calcium Waves and Side-Branch Formation in P. patens

Cuny Baruch College, New York NY

Investigators

Abstract

Light activates a series of specific photoreceptors and initiates a complex series of signal transduction events that result in dramatic developmental, physiological, and biochemical changes in the plant. At least three classes of light receptors (cryptochromes, phototropins, phytochromes) are involved in sensing the ambient light conditions. While phytochromes absorb in the red and far red regions, cryptochromes and phototropins absorb in the blue and UV-A regions. Although Ca2+ has been identified as a key second messenger in many signaling pathways, its role in photoreceptor signaling in a single plant cell has not been established. In a previous study, calcium ratio imaging using Fura 2 was used to measure cytoplasmic calcium in dark-growing caulonemal cells of the moss Physcomitrella patens. Fortuitously, the UV-A light needed to quantify calcium stimulated the photoreceptor system, making this approach an important means to study the role that calcium plays in photoreceptor signaling. P. patens mutants that are without cryptochrome genes have been made available to us. Calcium signaling and side branch formation will be examined in these plants to determine the role of calcium as a second messenger in cryptochrome signal transduction.